Just speedy test :)
Making hull will be better with Loft function :)
Ultra basic minima modele :O)
I am not sure that this one floats :):):)

View top : Delete right part
In the other view kill curves generators
You have now only surfaces !
Just Show Points and move them as you want :)
Of course you can add any points :)
You will see that lofts are perfect for clean surfaces generating :)
If you see by hasard some artifacts, it's just the rendering view (light shadows) sytem of MoI :)

In another way try the fabulous Open Source "Free Ship"
http://freeship.sourceforge.net/
And you will can made everything from little boat to Petroleum tanker :)
It's like Moi a nurbs Modeler but + Subdivise Surfaces :)